Can anyone help to differentiate single molecular magnets and metal complex with respect to magnetism. Using magnetism as tool, how can I explain..
I find it hard to understand your question. For me, single molecule magnets and metal complexes have a considerable overlap. So, in what way do you want to differentiate them (only then can we meaningfully discuss their magnetic properties).
And with respect to your second sentence: what is it that you want to explain?
Dear Professor.,
Sorry for my typical way ofquestion.
We are preparing monomeric metal complex with simple ligands. Which have been tuned by varies ancillary ligands. Magnetic properties of this complexes enhanced with various ligands.
Is there any possible to call it as single molecular magnets.
How fair to seen these two type of magnetism ?
I may not be fully aware of how the terminology has evolved over the years, therefore take with some grain of salt what I write below.
To me, single molecule magnets (SMM's) are those molecules which (usually at very low temperature) show (maybe dynamical) hysteresis in their magnetization cycles even in absence of the presence of other molecules. These are not necessarily mononuclear (in terms of the number of sites with significant magnetic moments) molecules. I remember that in the 1990's very good work in this direction being done by Wernsdorfer, Barbara and coworkers in France.
It is also in the context of their work that I became aware of the phenomenon of quantum tunneling of magnetization (QTM).
Mononuclear metal complexes will most of the time (I believe) have a hard time to fit into this class of materials because the rate of QTM tends to be so fast that it is hard to get hysteretic behavior on typical experimental time scales. (Well that is talking in terms of magnetometry, which typically is a slow measurement. There exist fast probes of magnetic fluctuations, too, (e.g. Mößbauer spectroscopy), and things might be somewhat different there (I ignore)).
I can give you a counterexample: Co-Pc (Cobalt phthalocyanine) is a mononuclear complex with a nonzero magnetic moment (low-spin 1/2). As a single molecule it is paramagnetic, so it would not fit into my definition of a SMM above. By growing these molecules as films or crystals, however, ferromagnetism arises. This then is a collective effect, due to the interactions between the molecules. Again, not SMM behavior.
So, in order to find out whether your experimental findings are indicative of SMM behavior, you should be able to demonstrate that they're not a collective effect. In my imagination this will require some clever experiment design and maybe a plausible model demonstrating what happens (or what you imagine to happen) in the molecule.
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